1. Field of the Invention
This invention relates to a motor-powered material throwing or slinging apparatus useful in distributing loose bulk material such as grain, wood chips, powders and the like into areas such as under overhangs or into interior corners of a ship's hull or warehouse. My invention is directed towards a high volume material slinger which can quickly alter the angle of the ejected material without stopping the throwing or altering the tension or alignment of the material throwing belt. Also included is an air vent which allows free circulation of air into and or out of the material feed path to prevent possible air locks which might otherwise slow the feeding of material to the throwing belt.
2. Description of the Prior Art
Material slingers, throwers or trimmers as they are known in the field, fall into a relatively old and well developed art. One prior art disclosure pertaining to material slingers which is particularly useful in gaining an understanding of the basic structures and concepts relating to material slingers is U.S. Pat. No. 2,125,088 issued to A.D. Sinden on Jul. 26, 1938 and herein incorporated by reference. U.S. Pat. No. 2,125,088 is also helpful in understanding the basic mechanics used to rotationally connect a slinger to a vertically hanging tubular feed chute, and spin or rotate the slinger under motor power to direct the throwing of material during the loading of a ship. Other methods and structures for rotatably hanging and spinning slingers on feed chutes, belts or tubes are also known. Another particularly relevant prior art disclosure is U.S. Pat. No. 2,950,809 issued to A. D. Sinden on Aug. 30, 1960 and which is also incorporated herein by reference primarily because of the discussion of throwing belt support and tracking problems associated with material slingers. Another U.S. Pat. No. 2,950,808 issued to D. E. Gerberich on Aug. 30, 1960 is also helpful in understanding throwing belt support, tracking and tensioning in material slingers, and therefore is also incorporated herein by reference.
The majority of material slingers are used for trimming the holds of ships, with some being used for adding capacity to warehouses and extending existing outdoor stockpiles. The function of these material slingers is to eject bulk material at high speed and extended distances into areas that otherwise would be difficult to access. Most of these material slingers utilize a wide, high speed rotating continuous belt for throwing the material to the desired location, which may be many feet from the ejection point. It is necessary to occasionally change the angle (trajectory), upward or downward, at which the material is thrown in order to better access certain areas. Many prior art material slingers change the curvature of the belt from which the material is ejected to alter the angle of projection, that is, throw the material at a higher or lower angle. This is generally accomplished by depressing the top central surface of the belt with two idler wheels, one idler wheel placed on each outer edge of the top surface of the belt. Retracting the idler wheels decreases the curvature of the belt and ejects the material more horizontally, while increasing the curvature of the belt ejects the material in a more upward arch. The main material throwing belt of a slinger is normally supported by a rotatable front wheel and a rotatable rear wheel, with each belt support wheel supported by an axle. The throwing belt is wrapped around the front and rear support wheels, and one of the support wheels or the axle thereof is rotationally driven by an electric motor, which causes the throwing belt to rotate. The axles supporting the belt support wheels must be in near perfect parallel alignment with one another in order for the belt to track in the center of the belt support wheels and to not wander to one side. In order to alter the curve of the throwing belt to change to trajectory of the ejected material as is common in the prior art, facilities must be provided to allow the belt support wheels and axles to either move closer or further from one another as the idler wheels are adjusted upward or downward on the top of the throwing belt, and this most often leads to the tension of the belt being altered, and additionally also normally leads to the wheel support axles becoming slightly out of parallel with one another, thus leading to belt wandering. Thus the disadvantage of this method of altering the ejecting angle of the thrown material is that keeping the throwing belt tracking properly can be very difficult, and altering the tension and curvature of the belt can often throw it out of alignment causing the belt to wander to one side. If the belt wanders, it can become damaged and ruined when it collides with side frame members of the slinger, and there is a significant amount of down time and cost involved in replacing a belt of this nature. A throwing belt can wander to one side and be ruined within just a couple of seconds of running time, which usually does not give the operator time to shut down the machine before the very expensive belt has been damaged.
Another problem associated with prior art slingers is, and most likely always will be, the volume of material which can be moved in a given amount of time. When loading ships, the faster the loading job can be accomplished, the sooner the ship can get underway, which can equate to more loads per year being delivered and possibly higher profits. Therefore there exists the need for an improved arrangement of altering the angle at which the material is ejected from slingers, and further for higher volume slingers which are readily controllable during operation.